Public Key Authentication Device, Public Key Authentication System, Public Key Authentication Method, and Program

1. A public key authentication device comprising one or more processors and memory storing one or more instructions, which when executed by the one or more processors, causes the one or more processors to perform operations comprising: receiving, from a calling-side telephone set, an invitation requesting for connecting to a receiving-side telephone set using Session Initiation Protocol (SIP) and a public key certificate stored in an Integrated Circuit (IC) card associated with a caller of the calling-side telephone set, wherein the public key certificate includes a public key and a serial number of the caller; checking validity of the received public key certificate with an authentication server configured to authenticate the validity of the public key certificate; generating a random number in response to confirmation of the validity; transmitting the random number to the calling-side telephone set; receiving a locked random number from the calling-side telephone set by attaching an electronic signature to the random number using a private key stored in the IC card, wherein the private key is paired with the public key; performing a signature verification on the locked random number using the public key to convert the locked random number back to the random number; search a database (DB) for the serial number of the caller, wherein the serial number is associated with personal identity information of the caller; verifying that the caller is legitimate by authenticating the personal identity information; and enabling a telephone call connection between the calling-side telephone set and the receiving-side telephone set.

2. The public key authentication device according to claim 1, the operations further comprising: providing a list including at least one receiving-side telephone number, one or more serial numbers of different callers associated with the at least one receiving-side telephone number, and acceptance or rejection of receiving a telephone call associated with each serial number; determining whether or not the received serial number in the received public key certificate is in the list; in response to determining that the received serial number is in the list, detecting the acceptance of receiving a telephone call associated with the received serial number from the list; and in response to detecting the acceptance of receiving the telephone call, obtaining a receiving-side telephone number associated with the received serial number from the list.

3. The public key authentication device according to claim 1, further comprising: receiving, from the receiving-side telephone set, a request for authentication of the caller during the telephone call; providing a list including at least one receiving-side telephone number, one or more serial numbers of different callers associated with the at least one receiving-side telephone number, and notification information associated with each serial number; determining whether or not a receiving-side telephone number of the receiving-side telephone set is in the list; in response to determining that the receiving-side telephone number is in the list, determining whether or not the received serial number in the received public key certificate is in the list; in response to determining that the received serial number is in the list, identifying notification information associated with the received serial number; and transmitting the notification information, as the result of the request for authentication, to the receiving-side telephone set.

4. A public key authentication method performed by a public key authentication device configured to personally authenticate a caller, comprising: receiving, from a calling-side telephone set, an invitation requesting for connecting to a receiving-side telephone set using Session Initiation Protocol (SIP) and a public key certificate stored in an Integrated Circuit (IC) card associated with a caller of the calling-side telephone set, wherein the public key certificate includes a public key and a serial number of the caller; checking validity of the received public key certificate with an authentication server configured to authenticate the validity of the public key certificate; generating a random number in response to confirmation of the validity; transmitting the random number to the calling-side telephone set; receiving a locked random number from the calling-side telephone set by attaching an electronic signature to the random number using a private key stored in the IC card, wherein the private key is paired with the public key; performing a signature verification on the locked random number using the public key to convert the locked random number back to the random number; search a database (DB) for the serial number of the caller, wherein the serial number is associated with personal identity information of the caller; verifying that the caller is legitimate by authenticating the personal identity information; and enabling a telephone call connection between the calling-side telephone set and the receiving-side telephone set.

5. A non-transitory computer readable medium storing one or more instructions causing a computer to function as a public key authentication device to execute: receiving, from a calling-side telephone set, an invitation requesting for connecting to a receiving-side telephone set using Session Initiation Protocol (SIP) and a public key certificate stored in an Integrated Circuit (IC) card associated with a caller of the calling-side telephone set, wherein the public key certificate includes a public key and a serial number of the caller; checking validity of the received public key certificate with an authentication server configured to authenticate the validity of the public key certificate; generating a random number in response to confirmation of the validity; transmitting the random number to the calling-side telephone set; receiving a locked random number from the calling-side telephone set by attaching an electronic signature to the random number using a private key stored in the IC card, wherein the private key is paired with the public key; performing a signature verification on the locked random number using the public key to convert the locked random number back to the random number; search a database (DB) for the serial number of the caller, wherein the serial number is associated with personal identity information of the caller; verifying that the caller is legitimate by authenticating the personal identity information; and enabling a telephone call connection between the calling-side telephone set and the receiving-side telephone set.

6. The public key authentication method according to claim 4, further comprising: providing a list including at least one receiving-side telephone number, one or more serial numbers of different callers associated with the at least one receiving-side telephone number, and acceptance or rejection of receiving a telephone call associated with each serial number; determining whether or not the received serial number in the received public key certificate is in the list; in response to determining that the received serial number is in the list, detecting the acceptance of receiving a telephone call associated with the received serial number from the list; and in response to detecting the acceptance of receiving the telephone call, obtaining a receiving-side telephone number associated with the received serial number from the list.

7. The public key authentication method according to claim 4, further comprising: receiving, from the receiving-side telephone set, a request for authentication of the caller during the telephone call; providing a list including at least one receiving-side telephone number, one or more serial numbers of different callers associated with the at least one receiving-side telephone number, and notification information associated with each serial number; determining whether or not a receiving-side telephone number of the receiving-side telephone set is in the list; in response to determining that the receiving-side telephone number is in the list, determining whether or not the received serial number in the received public key certificate is in the list; in response to determining that the received serial number is in the list, identifying notification information associated with the received serial number; and transmitting the notification information, as the result of the request for authentication, to the receiving-side telephone set.

8. The non-transitory computer readable medium according to claim 5, wherein the one or more instructions further cause the computer to execute: providing a list including at least one receiving-side telephone number, one or more serial numbers of different callers associated with the at least one receiving-side telephone number, and acceptance or rejection of receiving a telephone call associated with each serial number; and determining whether or not the received serial number is in the list; in response to determining that the received serial number is in the list, detecting the acceptance of receiving a telephone call associated with the received serial number from the list; and in response to detecting the acceptance of receiving the telephone call, obtaining a receiving-side telephone number associated with the received serial number from the list.

9. The non-transitory computer readable medium according to claim 5, wherein the one or more instructions further cause the computer to execute: receiving, from the receiving-side telephone set, a request for authentication of the caller during the telephone call; providing a list including at least one receiving-side telephone number, one or more serial numbers of different callers associated with the at least one receiving-side telephone number, and notification information associated with each serial number; determining whether or not a receiving-side telephone number of the receiving-side telephone set is in the list; in response to determining that the receiving-side telephone number is in the list, determining whether or not the received serial number is in the list; in response to determining that the received serial number is in the list, identifying notification information associated with the received serial number; and transmitting the notification information, as the result of the request for authentication, to the receiving-side telephone set.